Links to fotos of Blyth pubs.
http://communities.northumberland.gov.uk/005420FS.htm
Star and Garter in middle, kings Head beyond, from the south
This photo of the (Northumberland Street) Star & Garter is dated c.1900 compared to the picture of the (Brewery) Star & Garter which is dated c.1920. But the (Northumberland Street) building was the Star & Garter within Michael's living memory, so the (Brewery) pic must be much earlier than labelled. Or not the Star and Garter at all...
Here's a list of inns, taverns & public houses for "Blyth and neighbourhood" transcribed from the 1828/29 Pigot's Commercial Directory:
Bear (High Pans)
Black Bull (Blth - sic)
Coal Wagon (Foley)
Dun Cow (Blyth)
Half Moon (Blyth)
King's Arms (Cowpen Green)
King's Head (Blyth)
Lord Nelson (Blyth)
Nag's Head (Blyth)
Phoenix (Blyth)
Red Bull (Keelman's Row)
Seven Stars (North Blyth)
Ship (Blyth)
Ship (North Blyth)
Star & Garter (Blyth)
Turk's Head (Blyth)
Waterloo Hotel (Waterloo)
Back to the original post, and assuming that pubs tend to be located where the bulk of the population lived, it seems that even in 1828/29 Blyth rather than Cowpen was the label of choice, at least for Messrs Pigot. The accompanying text refers to "A considerable portion of the town of Blyth extends into the Township of Cowpen, in the parish of Horton. The population of the place must therefore be taken including its several suburbs which, in 1821, contained together 3,000 inhabitants."
Duncan.